Ben, Gwen, and Kevin are sent to investigate an attack by Pyroxivors (a race of subterranean alien cattle) on an oil drilling operation. Deep underground, they discover the humanoid mole-like alien named Moldywarp, their owner. He explains that the creatures were driven above ground by Vulkanus, who has been secretly drilling into the Earth’s depths. He plans to drop a bomb into the earth’s core, thereby raising the temperature of Earth to match that of his home planet. Ben manages to stop the bomb before it can reach the core, and Moldywarp uses his cache of explosives to seal the cavern permanently.